This invention is a system to transmit data by modulating-demodulating a microwave to obtain two-way communication between a fixed station, known as a beacon or reader, and a mobile station, known as a badge or transponder. More precisely, the invention applies to the system architecture which is organized to allow simultaneous data exchanges (full duplex) instead of alternated exchanges (half duplex) between a beacon and at least one badge. The microwave range allows the beacon to interrogate a large number of badges with no collisions between the streams of data exchange.
This type of data exchange is used to monitor moving bodies, for example to identify trucks on a track, cars at a toll barrier or pedestrians at the entrance to a building; in these cases, the badges move in front of a stationary reader. Nonetheless, when searching for an item, the badges may be fixed, mounted on an item sought, and the reader then moves until it finds the item sought; by convention, to make the explanation of the invention clearer, the terms "reader" and "responder-badge" or "transponder" will still be used, even if the reader is mobile and the badge fixed.